SK162198A3 - Method and device for the purification of sewage - Google Patents

Abstract

The method of wastewater treatment is biological via a hovering activation system with activated sludge. Into I. Activation stage, which also has a buffer tank function and the sludge, the sewage is fed and subsequently pumped into II. activation stage - reactor with discontinuous flow, where they are cleaned. Own bio-ionic cleaning takes place in stages wherein the activation phase occurs simultaneously in both I and II. activation stage - in two reactors with discontinuous operation flow. Because the filling phase II. activation stage occurs only after the sedimentation and emptying phases of the reactor, this time is also sufficient for separation sludge from pre-treated water in the 1st activation stage, which thus remains at the bottom of the tank, and II. the activation stage is then filled with pre-treated water without sludge. surplus activated sludge from II. activation stage returns to storage and further aerobic stabilization into the 1 st activation degree.

Description

Technical field

The invention relates to a biological treatment of wastewater using an activated sludge activated sludge system and an apparatus for carrying out a method which is particularly suitable for larger domestic treatment plants and industrial waste water.

BACKGROUND OF THE INVENTION

Biological wastewater treatment uses activated sludge, which is a mixture of different bacteria and microorganisms. This sludge needs for its life organic substances contained in waste water, which it decomposes and thus purifies waste water. The activation process is only possible with continuous oxygenation, which is usually solved by blowing air into the activation tank.

Wastewater treatment uses micro-organisms firmly attached to the substrate, in the form of various biofilter and bioreactor systems, which are wetted with wastewater, and also activated sludge activation systems where sludge flakes are mixed with wastewater and air.

Hitherto known wastewater treatment plants with suspended sludge can be divided into systems with continuous waste water flow through the activation tank and into systems with discontinuous flow (SBR).

In a continuous treatment system, the waste water is fed to the activation tank after a rough pre-treatment and after a technologically necessary time, when the water is purified, it is discharged together with the activated sludge to a separate settling tank. tank. In this tank, sludge is separated and clean water is discharged to the drain.

In a discontinuous flow system, the waste water is fed to the activation tank directly or after pumping from the buffer tank after a rough pre-treatment. After purification of the water, the activation process is interrupted, i.e. the aeration and eventual mixing of the water in the activation tank is stopped, and after separation of the sludge, the purified water is pumped or drawn off gravitationally to waste.

The activation tank is then refilled and the cycle is repeated. Compared to continuous cleaning, the settling tank is eliminated and the activation tank (SBR) is inflated cyclically.

A disadvantage of the SBR system is that the volume of the accumulation tank, which is usually upstream of the SBR reactor, is not used for wastewater treatment, and primary sludge is stored here, which is not aerobically stabilized and is therefore classified as hazardous waste.

SUMMARY OF THE INVENTION

The aforementioned drawbacks are eliminated by the two-stage activation process of wastewater treatment according to the invention, wherein the wastewater is first fed into the tank of the activation stage, which also has the function of a sludge tank and a buffer tank. From this tank, the waste water is pumped to the activation tank - SBR reactor.

The reactor operates sequentially in the following phases:

- performance

- activation (aeration)

- denitrification (mixing)

- sedimentation

- removal of clean water

- removal of excess sludge

The individual phases of the treatment are repeated cyclically and the lengths of the individual phases are adjusted on the control unit of the treatment plant depending on the amount and contamination of the waste water.

The essence of the invention is that the sewage is fed directly to the buffer tank upstream of the SBR reactor and also to the excess activated sludge from the reactor. During the reactor aeration phase, when the reactor is not being filled, the buffer tank is also aerated, whereby the waste water is pre-treated with excess sludge from the reactor, the sludge is further aerobically stabilized and at the same time the primary sludge sedimented in the waste water equalization tank. In all other purification phases in the SBR reactor, the buffer tank volume is at rest, the sludge settles at the buffer tank bottom, and in the filling phase, the pre-treated water without sludge remaining in the buffer tank bottom is pumped into the reactor. In fact, the lower volume of the buffer tank has the function of a sludge reservoir and the upper volume serves to store the sewage during the time when it is not possible to fill the reactor. In the aeration phase, the two volumes are mixed together to form the first activation stage.

The main advantage of the two-stage activation cleaning process in the SBR system is that it is possible to reduce the overall volume of the treatment plant tanks, since in the first activation stage the organic load is reduced by up to 50% and hygiene problems associated with disposal of primary sludge are eliminated. aerobically stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings show one possible embodiment of a two-stage activation treatment plant according to the invention. In FIG. 1 is a plan view of the treatment plant; FIG. 2 shows a vertical section and a schematic diagram.

DETAILED DESCRIPTION OF THE INVENTION

The activation plant of FIG. 1 and 2 is formed by two waterproof separate activation tanks. I. the activation stage consists of a buffer tank 1 and II. activation stage SBR 2 reactor. The buffer tank 1 serves to accumulate and equalize the uneven inflow and at the same time to collect coarse impurities and accumulate excess sludge from the reactor. Thus, a mixture of primary and excess activated sludge with a mixture of raw and pre-treated waste water is stored and intermittently aerated. In the buffer tank 1 there is an aeration system 4, a raw water pump 7 and a level sensor 16. The SBR 2 comprises an excess sludge pump 10, a clean water pump 9, an aeration system 8, a water level switch 15. Waste water is fed to the buffer tank. 1, and from there in the feed phase of the reactor 2 are pumped through the raw water pump 7 to the reactor 2.

After the reactor has been filled to a maximum level of 13, the reactor filling phase 2 is complete and the activation phase begins, in which the reactor volume is aerated. At the same time, the buffer tank 1 is also aerated by opening the solenoid valve 19, respectively by starting a separate blower (not shown). Upon completion of the set activation phase time, the denitrification phase occurs in which the reactor volume is stirred, because the set-up phase occurs directly. After the installation is completed, the purified water with a volume between max. 13 and the cut-off level of the clean water pump 12, and then the excess sludge with part of the purified water is pumped to the buffer tank. Χ The sludge pumping is terminated after the cut-off level of the sludge pump 20 has been reached. after reaching the cut-off level of the sludge pump 2, the emptying of the reactor 2 is completed and thus the control unit is instructed to proceed to the next stage of the reactor loading.

If sufficient sewage flow is not ensured and the pumping of reactor 2 takes too long, the control unit briefly triggers the reactor 17 to aerate the reactor 2 at set intervals to maintain the aerobic environment there. In order to avoid mixing the buffer tank 1 and then pumping the sludge into the reactor 2 in these cases, the buffer tank blower (not shown) is closed in all phases except for the activation electrovalve 19. the end of the sedimentation and emptying phase of the reactor 2, the sludge in the buffer tank 1 always has sufficient time for proper settling at the bottom of the buffer tank 1, and the sludge level 5 is thus always well below the inlet of the raw water pump 7.

Typically, the system is supplemented by sensing the maximum water level in buffer tank 6. Upon reaching it, the phases of each phase are automatically reduced to the set minimum values to increase the hydraulic capacity of the treatment plant.

The legend:

-1. activation stage - buffer tank

- II. activation stage - SBR reactor

- waste water inflow

- aeration device

- sludge level after settling

- the maximum level in the buffer tank

- raw water pump

- aeration device

- clean water pump

- pump of excess sludge

- the sludge level in the reactor after substitution

- cut-off level of the clean water pump

- maximum level in the reactor

- controller

- pressure level sensor

- pressure level sensor

- blower - compressor

- air distribution

- electric valve

- switch-off level of sludge pump (s) / 62 / -7 /

Claims (5)

1. Method of two-stage waste water treatment with biological activated sludge, in which the first activation stage, which has the function of both a buffer tank and a sludge tank and includes an aeration device, an accelerated level switch and a raw water pump, is supplied with waste water and subsequently are pumped through a raw water pump for purification in a reactor comprising an aeration device, a clean water pump, an excess sludge pump and a level sensor, characterized in that the activation phases in the I. and II. Activation stage takes place at the same time and only after the reactor is filled to the maximum level, while further filling of the reactor occurs after the time technologically necessary for settling of sludge at the bottom of the reactor and its emptying. filling the reactor with pre-treated water without sludge from the first activation stage. Wastewater treatment method according to claim 1, characterized in that the steady concentration if the sludge in the reactor is maintained automatically by the height of the sludge pump inlet above the bottom of the reactor, so that an optimum sludge volume remains in the reactor after each cycle. Wastewater treatment method according to claim 1, characterized in that when the water level in the buffer tank rises to the maximum level, the set times of the individual treatment stages are automatically reduced to a technological minimum and thus the maximum hydraulic capacity of the treatment plant is increased. 4. Two-stage discontinuous activation waste water treatment plant with biological activated sludge with simultaneous aeration of I. and II. activation stage, where the 1st activation stage consists of a buffer tank with waste water inflow, aeration device, raw water pump for pumping from the buffer tank to the II. activation stage - a SBR reactor comprising a clean water pump, a surplus sludge pump, an aeration device and a level meter, characterized in that the time technologically required for sedimentation of the sludge in the reactor (2) and its emptying before further charging is sufficient separating the sludge from the pre-treated water in the buffer tank (1) - the first activation stage - before starting the next phase of filling the reactor (2) with this pre-treated water. 5. Two-stage discontinuous activation sewage treatment plant with biological activated sludge with simultaneous aeration of I. and II. An activation stage, characterized in that the optimum amount of activated sludge in the reactor (2) is determined by the inlet height of the excess sludge pump (10) above the bottom of the reactor.